I. Technical Field
The present invention relates to a seat having a seat adjustment device into which there is incorporated a clutch unit having a lever side clutch section transmitting operational torque from the input side to the output side and a brake side clutch section transmitting rotational torque from the input side to the output side and shutting off reverse input torque from the output side.
II. Description of the Related Art
Generally speaking, in a clutch unit using engagement members such as cylindrical rollers or balls, a clutch section is arranged between the input side member and the output side member, and, in the clutch section, the engagement members such as cylindrical rollers or balls are engaged/disengaged with/from a wedge gap formed between the input side member and the output side member, thereby controlling the transmission/interruption of the input torque.
A clutch unit of this type is sometimes incorporated, for example, into a seat adjustment device which vertically moves a seat through lever operation to be used (see, for example, JP 2003-93187 A and JP 2002-240601 A). This clutch unit is equipped with a lever side clutch section transmitting rotational torque from the input side to the output side and a brake side clutch section transmitting rotational torque from the input side to the output side and shutting off reverse input torque from the output side.
In the seat adjustment device, an input side member of the lever side clutch section is coupled to a lever, and an output side member of the brake side clutch section is coupled to a rotary member vertically moving the seat. By performing a pumping operation on the lever upwardly or downwardly, the rotational torque is transmitted to the output side member to rotate the rotary member by inching, whereby the seat is vertically moved, thus enabling the seat surface adjustment thereof.
When the occupant is seated on the seat, even if rotational torque is applied to the output side member via the rotary member, the output side member is locked by the reverse input rotational torque thereof, thus preventing the input side member from rotating.